Indicator tapes and methods

ABSTRACT

Sterilization indicator tapes utilizing moisture-resistant, water-dispersible, pressure sensitive adhesives are provided. The indicator tapes comprise a non-water-dispersible backing having a sterilization indicator thereon, which is coated on at least one side with the moisture-resistant, water-dispersible, pressure sensitive adhesive. The indicator tapes are useful to maintain a sterilization wrapper containing articles to be sterilized in a closed position during sterilization, and normal pre- and post-sterilization handling, while also providing a means to indicate if the wrapped articles have passed through a sterilization cycle. After use, the adhesives coating the indicator tapes disperse in aqueous alkali solutions, such as are found in commercial laundries, while the backing remains intact. Methods of making and using the indicator tapes are also provided.

This is a continuation of application Ser. No. 07/889,647 filed May 28,1992, now abandoned.

FIELD OF THE INVENTION

This invention relates to sterilization indicator tapes utilizingwater-dispersible pressure sensitive adhesives and to methods of usingthe same.

BACKGROUND OF THE INVENTION

A variety of products such as gowns, sheets, drapes, instruments, etc.which are required during surgery, or other aseptic procedures, are usedon a daily basis in the normal operation of hospitals, clinics and thelike. Where such products are not pre-packaged in a sterile state, it isnecessary for the hospital or clinic to sterilize them before use.Furthermore, where these products are not disposable, and are employedmore than once, it is necessary that they be cleaned and otherwiseprepared for subsequent use. Prior to such use, however, it is essentialthat such products be sterilized.

Due to the volume of materials involved, it is often necessary tosterilize and store these products for use as desired. Accordingly,there has been developed a procedure where such products, aftercleaning, laundering and the like, are packaged in cloth sterilizationwrappers for subsequent use, and the wrapped package is then sterilizedand stored. As may be apparent, there is a potential danger in such aprocedure. There is a prospect of unsterilized packages becoming mixedwith sterilized packages when stored for use.

To prevent unsterilized products from being used by the physician orattendant requiring sterile materials, various types of sterilityindicators which are attached to, or incorporated into, the wrappedsterilization package have been developed. This permits a user toimmediately determine whether a particular package has been passedthrough the sterilizer. Although such sterilization indicators have, inmany instances, been placed in the wrapped package or attached to thewrapped package, the most convenient way of applying such sterilizationindicators is to have the sterilization indicators carried by pressuresensitive adhesive indicator tapes used for holding the cloth wrapper ina closed position prior to, during, and after sterilization of theenclosed products.

Various pressure sensitive adhesives have been used with tape backingsthat include appropriate color changing means to indicate if the packagehas been exposed to sterilization conditions. Examples of pressuresensitive adhesives employed with such indicator tapes include waterinsoluble natural rubber based adhesives, natural rubber and syntheticrubber blend adhesives, styrene-isoprene-styrene block copolymers withtackifying resins, vinyl ethers, and high molecular weight acrylatecopolymers having minimal amounts of plasticizing monomers includedtherein. See e.g., U.S. Pat. Nos. 2,889,799, 3,067,057, 3,078,182,3,311,084, and 4,188,437. Typically, these indicator tapes use a paper,fabric or film backing, and an adhesive chemistry that is resistant tosoftening upon exposure to heat.

Cloth sterilization wrappers may be disposed or retained after use. Ifretained, the soiled cloth wrappers must be cleaned after use, usuallyby laundering in soapy water, such as an aqueous alkali solution. Thesewrappers will then be used to wrap items to be sterilized. The expenseof some cloth wrappers, such as treated synthetic wrappers and untreatedwrappers, demands that the closure and sterilization indicator tapes notdamage the wrapper after use.

The various indicator tapes referenced above are not formulated todisperse during cleaning, and in fact, if not manually removed beforelaundering, may permanently damage a sterilization wrapper.Specifically, the heat and chemicals associated with laundering anddrying of the sterilization wrappers will cause the pressure sensitiveadhesives used with the indicator tapes to flow into the fabric of thecloth wrappers, and thereby permanently damage the sterilizationwrapper.

Water-dispersible pressure sensitive adhesives have been made and usedfor paper making and printing operations which require splicing of theend of one roll of paper to the beginning of another roll. For example,U.S. Pat. Nos. 3,865,770, 4,413,080, 4,569,960, 3,441,430, and 2,838,421disclose such water-dispersible pressure sensitive adhesives and/orsplicing tapes made therefrom. Further examples of water-soluble orwater-dispersible pressure sensitive adhesive compositions, and/or tapesmade therefrom, can be found in U.S. Pat. Nos. 4,413,082, 4,341,680,4,388,432, 3,890,292, 3,763,117, 3,152,940, 3,096,202, and EuropeanPatent Publication Nos. 0 352 442 and 0 297 451. In addition, U.S.patent application Ser. No. 07/580,116 describes an autoclavablewater-dispersible pressure sensitive adhesive on a dispersible backingfor use as a means to adhere cloth to cloth or cloth to skin in areaswhere high amounts of fluid would be present.

To date, no indicator tapes utilizing water-dispersible, pressuresensitive adhesives exist. Thus, present indicator tapes must be removedfrom sterilization wrappers or other garments prior to laundering toavoid permanent damage to such articles.

SUMMARY OF THE INVENTION

The present invention uses water-dispersible pressure sensitiveadhesives to form sterilization indicator tapes which retain pressuresensitive adhesive properties after or during exposure to moistureand/or heat likely to be encountered in a sterilization process.Typically, the indicator tapes of the present invention are used to bothclose a sterilization wrapper used to contain articles to be sterilized,and to indicate that the wrapped package has passed through asterilization cycle. However, the indicator tapes of the presentinvention do not need to be removed from the sterilization wrappersprior to laundering. Thus, when the wrappers containing the indicatortapes are laundered, the water-dispersible, pressure sensitive adhesivescoating the indicator tapes disperse upon immersion in the aqueousalkali laundering solutions, while the tape backing containing thesterilization indicator, such as an indicator ink, stays intact.Preferably, but not necessarily, the immersion of the indicator tapesoccurs at elevated temperatures and considerable agitation, such asprevalent during a hot water laundry cycle.

In particular, the present invention provides an indicator tapecomprising a non-water-dispersible backing having opposing sides andincluding thereon a sterilization indicator, and a moisture resistant,water-dispersible, pressure sensitive adhesive coated on at least one ofthe opposing sides of the backing. Preferably, the sterilizationindicator comprises an indicator ink in combination with a binder. It isalso preferable that the indicator tape be capable of maintaining awrapped bundle of articles in a closed position during sterilization,and normal pre- and post-sterilization handling.

The present invention also provides a method making an indicator tapecomprising: (a) providing a non-water-dispersible backing havingopposing sides; (b) imprinting a sterilization indicator comprising anindicator ink in combination with a binder on one of the sides of thebacking, said indicator ink being capable of undergoing a color changewhen exposed to sterilization conditions; and, (c) coating amoisture-resistant, water-dispersible, pressure sensitive adhesive onthe opposing side of the backing.

The present invention further provides a method of using an indicatortape as a wrapper closure comprising: (a) providing an indicator tapecomprising a non-water-dispersible backing having opposing sides andincluding thereon a sterilization indicator, with a moisture-resistant,water-dispersible, pressure sensitive adhesive coated on at least one ofthe opposing sides of the backing; and, (b) applying the indicator tapeto a sterilization wrapper containing a bundle of articles such that thebundle will remain substantially closed during sterilization, and normalpre- and post-sterilization handling.

These and various other advantages and features of novelty whichcharacterize the invention are pointed out with particularity in theclaims annexed hereto and forming a part hereof. However, for a betterunderstanding of the invention, its advantages, and objects obtained byits use, reference should be had to the accompanying drawings anddescriptive matter, in which there is illustrated and describedpreferred embodiments of the invention.

Definitions

For the purposes of this invention:

"Non-water-dispersible backing" refers to a backing that will maintainsufficient physical integrity upon exposure industrial laundryconditions, such that the sterilization indicator contained thereon willnot separate from said backing.

"Normal and Pre- and Post-Sterilization handling" refers to handling ofwrapped bundles or packs that would likely occur in the day to dayoperation of hospitals, clinics, laudries and the like. This can includeloading of packs into and out of sterilizers, placement of packs intostorage, and movement of packs throughout and inbetween institutions.

"Sterilization Wrapper" or "Wrapper" refers to a covering, typicallymade of cloth, used to wrap an item or items to be sterilized by steam,gas, etc., and in fact may be formed by the outer side of an item to besterilized. Preferably, but not necessarily, the sterilization wrapperis reusable. Cloth is defined in its broadest sense to be fabric ormaterial formed by weaving, knitting, knotting, pressing, bonding,crocheting, interlocking, interlacing, melt-blowing, or felting ofnatural or synthetic yarns, filaments, or fibers. Nonlimiting examplesof cloth include woven, knitted or non-woven fabrics and webs, used assterilization wrappers.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be further illustrated by reference to theaccompanying Drawings wherein:

FIG. 1 is an expanded view of an embodiment of an indicator tapeaccording to the present invention;

FIG. 2 is a graph of the initial adhesion of the indicator tapes ofExamples 1-7 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 3 is a graph of the initial adhesion of the indicator tapes ofExamples 8-14 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 4 is a graph of the post-sterilization adhesion of the indicatortapes of Examples 1-7 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 5 is a graph of the post-sterilization adhesion of the indicatortapes of Examples 8-14 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 6 is a graph of the initial adhesion of the indicator tapes ofExamples 15-21 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 7 is a graph of the initial adhesion of the indicator tapes ofExamples 22-28 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 8 is a graph of the initial adhesion of the indicator tapes ofExamples 46-52 to untreated sterilization wrappers and tofluorochemically-treated polyester sterilization wrappers;

FIG. 9 is a graph of the pre-sterilized (initial) adhesion andpost-sterilized adhesion versus parts plasticizer of Example indicatortapes Nos. 48 and 53-55 on untreated sterilization wrappers;

FIG. 10 is a graph of the pre-sterilized (initial) adhesion andpost-sterilized adhesion versus parts plasticizer of Example indicatortapes Nos. 48 and 53-55 on fluorochemically-treated polyestersterilization wrappers;

FIG. 11 is a graph of the pre-sterilized (initial) adhesion andpost-sterilized adhesion versus the coating weight of adhesive ofExample indicator tapes Nos. 48 and 57-58 on untreated sterilizationwrappers; and,

FIG. 12 is a graph of the pre-sterilized (initial) adhesion andpost-sterilized adhesion versus the coating weight of adhesive ofExample indicator tapes Nos. 48 and 57-58 on fluorochemically-treatedpolyester sterilization wrappers.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Indicator Tapes

FIG. 1 illustrates a preferred indicator tape according to the presentinvention. The indicator tape includes a non-water-dispersible backing10 that is coated with a layer of moisture-resistant, water-dispersible,pressure sensitive adhesive 20. Markings formed of a sterility indicator30, such as a sterilization indicator ink, are printed on the backing10. While the sterility indicator 30 is printed in a diagonal pattern inFIG. 1, it will be appreciated that any pattern, and/or variations intotal surface area covered, could be encompassed by the printedsterility indicators 30 upon the non-water-dispersible backing 10.

Water-Dispersible Pressure Sensitive Adhesive Components PressureSensitive Adhesive Copolymer

The indicator tapes of the present invention utilize amoisture-resistant, water-dispersible, pressure sensitive adhesive tocoat at least one side of a non-water-dispersible backing with asterilization indicator thereon. In this regard, it is preferred thatthe water-dispersible adhesive comprise an acrylate-based adhesivecopolymer in combination with a plasticizer.

In a preferred embodiment, the acrylate-based adhesive copolymer iscomprised of about 50-85 weight percent of at least one monomericacrylic acid ester of non-tertiary alkyl alcohol having 2-8 carbon atomsand correspondingly about 50-15 weight percent of a vinyl carboxylicacid monomer. Of the acrylic acid esters of non-tertiary alkyl alcohols,butyl acrylate is preferred. Of the vinyl carboxylic acids, acrylic acidis preferred. The adhesive copolymer desirably may comprise about 60-80weight percent of butyl acrylate and correspondingly about 40-20 weightpercent of acrylic acid. Preferably, the adhesive copolymer of butylacrylate and acrylic acid has a weight percent ratio of 75:25.

The adhesive copolymer should have a sufficient inherent viscosity toprovide appropriate adhesion to a sterilization wrapper. In this regard,the adhesive copolymer should have an inherent viscosity of from about 1g/dl to about 3 g/dl. Desirably, the inherent viscosity range for thecopolymer is between about 1.2 g/dl and 2.3 g/dl, and more preferablybetween about 1.2 g/dl and 1.3 g/dl.

Plasticizer

The plasticizer component of the water-dispersible, pressure sensitiveadhesive may comprise one or more water-dispersible or water-solubleplasticizers, or a combination of water-soluble and water-dispersibleplasticizers. Nonlimiting examples of suitable water-dispersible orwater-soluble plasticizers include a free acid or a sodium salt of acomplex organic phosphate ester, or a colophony (rosin) ester having aglass transition temperature (Tg) lower than the Tg of the pressuresensitive adhesive copolymer. Desirably, the plasticizer may be apoly(oxy-1,2-ethandiyl), alpha-(nonylphenyl)-omega-hydroxy-phosphateplasticizer, RHODAFAC PE-510™ (Rhone Poulenc, Cranbury, N.J.; formerlymade by GAF Corporation, as GAFAC PE-510™); or apoly(oxy-1,2-ethandiyl), alpha-nonylphenyl-omega-hydroxyphosphateplasticizer, such as RHODAFAC RE-410™ (Rhone Poulenc; formerly made byGAF Corporation as GAFAC RE-410™), or a combination thereof.

Plasticizers are chosen to optimize adhesion properties to a givenfabric substrate. Specifically, the plasticizers used in thewater-dispersible pressure sensitive adhesive compositions of thepresent invention should be selected based on their ability to increasethe flow of the pressure sensitive adhesive copolymer into the weave ofthe sterilization wrapper. In this regard, the RHODAFAC PE-510™ is aparticularly preferred plasticizer according to the present invention.

Tackifier

The tackifier is an optional additive to the water-dispersible pressuresensitive adhesive. If present, the tackifier is preferably a resin suchas an aromatic hydrocarbon resin, or a colophony (rosin) acid compatiblewith acrylate copolymers. Suitable tackifier resins for acrylatecopolymers are described in Satas, Ed., Handbook of Pressure SensitiveAdhesives, 2nd. Ed., (Van Nostrand, 1989), Chapters 20-22, thedisclosure of which is incorporated by reference. A preferred colophonyacid tackifier is FORAL AX™ (Hercules Corporation, Wilmington, Del.).

Controlling Properties of the Pressure Sensitive Adhesive

The water-dispersible, pressure sensitive adhesive is the blendedproduct of 100 parts by weight of the adhesive copolymer, from about 10to about 250 parts by weight of one or more plasticizers, optionallyfrom 0 to about 100 parts by weight of an acrylate-compatible tackifier,and sufficient molar amounts, if any, of a neutralizing agent in orderto control neutralization of the pressure sensitive adhesive to maintainoptimal properties of withstanding sterilization conditions and initialadhesion to sterilization wrappers.

Desirably, the pressure sensitive adhesive is the blended product of 100parts by weight of the adhesive copolymer, from about 80 to about 150parts by weight of plasticizer, from about 20 to about 60 parts byweight of an acrylate-compatible tackifier, and sufficient molar amountsof a neutralizing agent, if any, in order to control neutralization ofthe pressure sensitive adhesive so as to maintain moisture resistanceduring and after sterilization, provide needed adhesion and strength forpre- and post-sterilization handling of wrapped bundles, and stillprovide water dispersibility during cleaning.

Preferably, for each 100 parts by weight of the adhesive copolymer, theplasticizer may comprise about 120 parts by weight and the tackifier maycomprise about 25 parts by weight.

Variation of the amounts of the components blended to form thewater-dispersible-pressure sensitive adhesive of the present inventioncan be used to control the effective properties of the adhesive, bothduring sterilization, and with respect to normal pre- andpost-sterilization handling. For example, variation in the amount ofincorporated plasticizer, the coating weight of the adhesive, and theamount of neutralizing agent employed to neutralize the acid groups ofthe adhesive can be used to increase the adhesion of the indicator tapesto the sterilization wrappers.

If used, the neutralizing agent may be one or more alkali metalhydroxides present in an amount sufficient to cause the pressuresensitive adhesive adhesion properties to withstand steam sterilization,(typically 6 minutes at 134° C. at 100% humidity at 2 bar pressure) orethylene oxide sterilization (typically 30 minutes at 37° C. at 2 barpressure), and normal pre- and post-sterilization handling. Also, thepressure sensitive adhesive must have sufficient dispersibility in anaqueous alkali solution after the cloth sterilization wrapper has beenused.

If used, the neutralizing agent is preferably present in a molar amountsufficient to neutralize not more than 50% of the adhesive copolymeracid moiety. However, higher percent neutralization can be used, as thenon-dispersible backing prevents moisture penetration into the adhesive,and thereby prevents pre-mature dispersal of the adhesive. It ispreferred to keep the percent neutralization less than 100% as free basecan migrate and interact with many of the ink chemistries used assterilization indicators. While the plasticizer and tackifier may haveacid moieties therein, the present invention finds that the base moietyis more apt to neutralize the adhesive copolymer acid moiety because thedissociation constant (pKa) of the adhesive copolymer acid moiety in thesolvent used to prepare the pressure sensitive adhesive is 2.5 timeshigher than the pKa of the preferred plasticizer and 7 times higher thanthe pKa of the preferred tackifier.

Preferably, to achieve a balance of the functional properties of initialadhesion, wrapper closure, and moisture resistance to sterilization, andability to withstand normal pre- and post-sterilization handling, theamount of neutralizing agent present in the blended reaction productshould be sufficient to neutralize from about 12.5% to about 37.5% ofthe adhesive copolymer acid moiety. In this regard, it has beendiscovered that the property of initial adhesion of the pressuresensitive adhesive to a cloth sterilization wrapper obtains a maximumbetween about 0% and about 25% neutralization. Post-sterilized adhesionof the pressure sensitive adhesive remains relatively unchanged withincreasing neutralization of the adhesive copolymer acid moiety on bothuntreated 100% cotton wrappers and on 100% polyester, fluorochemicallytreated wrappers. All formulations of the adhesive were completelydispersible in an industrial laundry cycle.

A further means to increase the initial adhesion of the indicator tapesof the present invention to a sterilization wrapper it to increase theamount of plasticizer in the adhesive composition. In this regard, aplasticizer level of about 120 parts by weight of the preferred PE-510plasticizer has proven most effective at increasing the initial adhesionof the indicator tapes to the wrappers. However, there is a limit to theability to increase plasticizer levels in the adhesive composition.Specifically, too high of a plasticizer level will result in a loss ofcohesive properties of the water-dispersible adhesive coated on theindicator tapes of the present invention.

Yet another manner of increasing the initial adhesion of the indicatortapes of the present invention is to increase the coating weight of theadhesive coated on the indicator tape backing. In this regard, a coatingof weight of from about 0.58 g/154.8 cm² to about 0.87 g/154.8 cm² hasbeen found desirable. Furthermore, a coating weight of about 1.04g/154.8 cm² helps facilitate the adhesion of the indicator tapes totreated sterilization wrappers, such as the fluorochemically-treatedpolyester WrapPel™ 2 wrappers (Standard Textile Co., Cincinnati, Ohio).

Preferably, to endure the harsh conditions of steam or ethylene oxidesterilization, yet be moisture resistant during use and be dispersibleupon immersion in aqueous alkali solutions, the water-dispersiblepressure sensitive adhesive should have an initial adhesion to cloth ofequal to or greater than 1 Newton per 2.54 cm, a post-sterilizedadhesion to cloth of greater that 2 Newton per 2.54 cm and hold thecloth sterilization wrapper closed upon exposure to a sterilizationcycle and be able to withstand normal pre- and post-sterilizationhandling of the sterile package.

Preparation of the Water-Dispersible Pressure Sensitive Adhesive

The monomeric acrylic acid ester of non-tertiary alkyl alcohol and thevinyl carboxylic acid are copolymerized with an azobisisobutyronitrileinitiator in accordance with the teaching of U.S. Pat. No. RE 24,906,the disclosure of which is incorporated by reference herein. Thepressure sensitive adhesive is prepared by blending into the resultingadhesive copolymer, in order, the plasticizer, the tackifier, (if any isto be added), and the neutralizing agent, (if any is to be added). Theblended pressure sensitive adhesive comprises solids in an organicsolvent in the range from about 20 percent to about 60 percent solidsand preferably from about 30 percent to about 50 percent solids. Thepreferred organic solvent system comprises ethyl acetate and methanolblended in a range from about 60:40 to about 90:10, and preferably80:20. Alternatively, water is also added to the solvent system toprovide a range of ratios of ethyl acetate:methanol:water of from about60:35:5 to about 80:15:5.

As will be apparent from the ranges indicated above, substantialvariations in composition are possible. For example, the use of higherpercentages of short-chain acrylates in a copolymer tends to increasethe hardness of the adhesive, decreasing its tackiness. In such event,it is desirable to use a comparatively higher percentage of plasticizer.On the other hand, high percentages of long chain acrylates increase thetackiness of an adhesive and reduce the need for plasticizers.Similarly, the higher the percentage of vinyl carboxylic acid in thecopolymer, the lower the degree of neutralization necessary to insurewater dispersibility. Well known acrylate monomers such as isooctylacrylate may increase the tackiness of the ultimate adhesive and improveits adhesion to cloth sterilization wrappers.

Non-Water-Dispersible Backing and Sterilization Indicator

The non-water-dispersible tape backing can be made from anynon-water-dispersible film, paper, or other material physically capableof withstanding the conditions of a given steam and/or ethylene oxidesterilization cycle. Nonlimiting examples of other suitable backingsinclude isotactic polypropylene backings, such as disclosed in U.S. Pat.No. 4,898,762, the disclosure of which is herein incorporated byreference, as well as latex-saturated paper backings, foil backings,woven and nonwoven backings, polyolefin-based film backings, such aspolyethylene backings, and also polyester film backings. Preferably, thetape backing comprises a 29 pound basis weight Kraft paper (M-2383Smooth Crepe Semi-Bleached Kraft Saturating Paper; Mosinee PaperCorporation, Mosinee, Wis.). The Kraft paper is chosen for its ease oftearing which is an important consideration for opening a wrappedsterilized pack.

The paper backing is coated with an ink capable of changing color uponexposure to the given conditions of a sterilization cycle. Virtually anyindicator ink can be used with the tape backings and water-dispersibleadhesives of the present invention, as long as the ink and adhesivecomponents do not react to cause pre-mature color development of theindicator ink. Thus, steam sterilization indicator inks, such as leadcarbonate-sulfur indicator inks, ethylene oxide sterilization indicatorinks, or both types of indicator inks, can be imprinted on the tapebackings of the present invention. See e.g., U.S. Pat. No. 3,667,916,the disclosure of which is herein incorporated by reference. Nonlimitingexamples of suitable inks according to the present invention aredisclosed in U.S. Pat. Nos. 3,386,807; 3,098,751; 3,360,337; 3,360,338;3,360,339; 3,862,824; 3,523,011; 4,382,063; 3,258,312; 3,627,469;3,852,034; 4,015,937; 4,094,642; 4,168,779; 5,064,576, U.K. Patent Nos.1 458 553, and 1 370 470, and EPO Publication Number 0 282 178, thedisclosures of which are all herein incorporated by reference.

The preferred ink for a steam sterilizer is a lead carbonate-sulfursystem in a binder system, gravure printed in lines onto the Kraft paperbacking. Preferably the ink system comprises 38% binder, 23% sulfur, 15%lacquer thinner, 23% lead carbonate, and 1% clay (available as BENTONE™38, NL Chemicals, Hightstown, N.J.).

Virtually any binder can be utilized with the indicator inks of thepresent invention, as long as the binder is capable of maintaining theutilized ink on the backing during laundering. Thus, the binder and inkmust be compatible. The preferred binder system is 24% nitrocelluloseethyl alcohol (Hercules Inc., Wilmington, Del.); 3% phenol-formaldehyderesin (BECKCITE™ 24-102, BTL Specialty Resins, Toledo, Ohio); 9%tricresyl phosphate; 14% butyl alcohol; 27% xylene and 23% butylacetate.

The ink printed Kraft paper is then strengthened using a vulcanizednatural rubber-wood rosin system coated onto the paper. Preferably, therubber system comprises 23% natural rubber (Goodyear Tire and RubberCo., Akron, Ohio); 6% zinc oxide (Sherwin Williams, Cleveland, Ohio); 3%titanium dioxide (Type A-140, New Jersey Zinc Co., Palmerton, Pa.); 29%wood rosin (TENEX™ 36-710, Reichold Chemicals Inc., Oakbrook, Ill.); 2%calcium lithol pigment (Hercules Inc., Wilmington, Del.); and 37%mineral spirits. The preferred vulcanizer used to crosslink the rubbersystem is 40% white mineral oil (Type #31 USP; AMOCO Chemical Corp.,Chicago, Ill.); 15% tetramethylthirum disulfide accelerator (RTVanderbilt Co., Norwalk, Conn.); and 45% ortho-pentamethylenethiuramsulfads (RT Vanderbilt Co.).

The printed, saturated paper backing is then treated to decreasemoisture penetration of the paper. Preferably an acrylate polymersolution is utilized. The preferred solution is 19% butyl alcohol, 0.2%phosphoric acid, 9% urea, 0.8% aqueous ammonia, 31% formaldehyde, 6%isopropyl alcohol, 10% acrylic polymer (ELVACITE™ 2044; E.I. dupontNemours, Wilmington, Del.); 9% butanol and 15% xylene.

To allow for the printed, saturated, and sealed paper backing to becoated with the water-dispersible adhesive and wound into useable form,a means of preventing the adhesive coating on one side of the printedpaper from transferring to the other side must be used. Silicone orother treated release papers can be used to prevent contact of theadhesive with the non-coated side of the paper backing. Another means isto provide for a release coating or low adhesion back size on the nonadhesive coated side of the tape backing. The preferred release methodis a low adhesion back size. Depending on the nature of the adhesive, aurethane based low adhesion backsize can be used. The preferred lowadhesion backsize to be coated on the non-adhesively coated side of thetape backing is a urethane backsize described in U.S. Pat. No.2,532,011, the disclosure of which is herein incorporated by reference.

The non-water-dispersible backing may optionally be coated with anadhesive priming agent to increase the bond of the adhesive to thebacking. The preferred priming agent is NEOPRENE™ N115, (E.I. dupontNemours, Wilmington, Del.).

The tapes are preferably manufactured on tape rolls for continuousfeeding for application to cloth sterilization wrappers.

Advantages of the Invention

The indicator tapes of the present invention can serve strictly as anindicator that a wrapped package has been sterilized, e.g., byattachment of the tape to the outside of the wrapped package. However,it is preferred that the indicator tapes of the present invention servea dual purpose. Specifically, it is preferred that the indicator tapesbe used to both hold the wrapped package in a closed position, and alsoprovide a means to indicate completion of a sterilization cycle.

Whether utilized for a single or dual purpose, the water-dispersiblepressure sensitive adhesives utilized on the indicator tapes of thepresent invention disperse when immersed in aqueous alkali solutions inless than about 40-60 minutes, for a range of laundering cycle timeswhile the non-dispersible backing remains intact. Thus, the dispersibleadhesive washes free from the laundered sterilization wrapper. Thus,hospitals or other users do not have to pre-maturely replace wrappersdamaged by sterilization tape or adhesive residue. However, thenon-water-dispersible backing ensures that indicator inks do notdisperse in the wash (i.e. remain intact), and thereby preventscontamination of the laundered garments or the environment.

Furthermore, the water-dispersible pressure sensitive adhesive utilizedon the indicator tapes of the present invention resist moisture and heatgenerated during use as a sterilization wrapper closure, and therebyavoid loss of adhesion at the time of sterilization. Even if someheat-mediated flow of the adhesive into the wrapper fabric occurs, thedispersibility of the adhesive ensures that the wrapper will not sufferany permanent damage. Also, the moisture resistance of the preferredtreated paper backing of the present invention further enhances themoisture resistance of the indicator tapes, and accordingly, theirability to stay adhered to a wrapped package during a sterilizationcycle.

Yet another advantage of the invention is that the water-dispersiblepressure sensitive adhesive indicator tape reduces the time forprocessing goods to be laundered. Specifically, inspection forsterilization tape or adhesive residue does not need to take place sincethe pressure sensitive adhesive will disperse in the cleaning cycle.

Yet a further advantage of the invention is that the water-dispersiblepressure sensitive adhesive indicator tape is tamper evident since ifthe tape is peeled from a sterilized wrapper it cannot be re-adheredbecause the adhesive remains on the wrapper thus indicating thatsterility has been compromised.

Test Procedures

Initial adhesion to untreated and treated sterilization wrappers

Samples of a fluorochemically-treated polyester wrapper and a untreated100% cotton wrapper (180 thread count) were cut into 5.08 cm by 15.24 cmstrips. Example indicator tapes were applied to the untreated andtreated wrappers, and were rolled twice with a 2 kg rubber roller.

One end of each of the sample wrappers was adhered to a set of jaws onan Instron Model 1122 tensile tester (Instron Corp., Canton, Mass.),while the corresponding end of the laminated indicator tape was adheredto an opposing set of jaws of the tensile tester. The example indicatortape was peeled from the surface of the treated and untreated wrappersat a essentially a 180° peel angle. The rate of jaw movement was 25.4cm/minute and the tensile tester recorded the force required to separatethe tape laminate from the wrapper. The results were recorded in Newtonsper 2.54 cm. A "B" in the column means that the backing broke or toreduring the test. The initial adhesion measurement derives from the factthat the dwell time of the tape on the wrapper was short; i.e., theexample tape was applied and peeled without a long residence time inbetween, and sterilization had not yet taken place.

Post-sterilization adhesion to untreated and treated sterilizationwrappers

The same method as the initial adhesion test was used for this test,except that prior to testing, the laminate of the example indicatortapes and treated and untreated wrappers was steam sterilized at 132° C.in a 4 minute, four-pulse prevacuum cycle with a 1 minute steam drytime. The sterilizer used was an Eagle 2013 sterilizer (AmericanSterilizer Co., Erie, Pa.). In addition, the laminate was allowed tocool at room temperature for a minimum of 4 hours before peel testing.The results were recorded in Newton per 2.54 cm, with a "B" in thecolumn indicating that the backing broke or tore during the test.

Pre-sterilization wrapper closure (T.sub.(0))

A bundle was produced by rolling towels to a cylindrical size ofapproximately 25.4 cm in length by 12.7 cm in diameter. The bundle oftowels were then wrapped using either a 76.2 cm² untreated 100% cottonwrapper (180 thread count), or a fluorochemically-treated polyesterwrapper (WrapPel™ 2; Standard Textile Co., Cincinnati, Ohio) by placingthe towel cylinder diagonally on one of the wrapper corners, and rollingthe cylinder towards an opposing corner, while tucking in side corners.Once completely wrapped, the bundle or pack was securely closed with anexample pressure sensitive adhesive indicator tape.

The wrapped bundle was allowed to sit at room temperature (20° C., 50%R.H.) for 12 hours. The packs were inspected to assure that theyremained closed. The results were recorded as follows: P means passed,bundle remains closed with no edge lift; P-E means passed, bundleremains closed with a slight lifting of the tape edge; F-P means failed,bundle is no longer closed due to tape popping off one side of pack; F-Cmeans failed due to tape curling up and off of wrapper.

Post-sterilization wrapper closure (T.sub.(A))

A wrapped bundle was produced as described above for thepre-sterilization wrapper closure test, except that the bundle wasimmediately exposed to a steam sterilization cycle at 132° C., 7 minute,four-pulse prevacuum cycle and a 15 minute steam dry time. The packswere inspected to assure that they remained closed and the adhesiveremained intact. The results were recorded as follows: P means passed,i.e. the bundle remained closed with no edge lift; P-T means passed,with a slight tear in the backing; P-E means passed, i.e. the bundleremains closed with a slight lifting of the edge; F means failed, i.e.the bundle is no longer closed; F-T means failed due to a tear in thebacking.

Dispersibility Test

Wrapped bundles were prepared using untreated 100% cotton wrappers (180thread count) and fluorochemically-treated polyester (WrapPel™ 2)wrappers, and were sterilized as described in the Post-sterilizationWrapper Closure Test. The wrappers were removed from the bundle, withthe example indicator tapes adhered to the wrappers, and laundered in a65 lb. load in a commercial washing machine (Milnor washer, Model No.36021BWE/AEA; Pillerin Milnor Corp., Kenner, La.). The wrappers wentthrough a typical laundry cycle for surgical linens including: (a) twotwo-minute alkaline flushes, one cold and one split between hot andcold, in a 0.1% Paralate 55 GL11™ Commercial Liquid Laundry Alkali(Ecolab Inc., St. Paul, Minn.); a two-minute hot water flush, aneight-minute hot detergent/suds wash using 0.1% of Paralate 55 GLW™Commercial Liquid Laundry Alkali, and 0.05% Kindet™ Commercial LiquidLaundry Detergent (Ecolab Inc.); a two-minute hot water flush, aneight-minute hot bleach using 0.17% of a 5.25% by weight sodiumhypochlorite solution bleach (Lerro Chemical Inc., Philadelphia, Pa.);three two-minute water rinses, one hot and two split between hot andcold; a four-minute cold sour/soft rinse using 0.05% Tri Liquid Sour55GL™ Commercial Liquid Laundry Sour (Ecolab Inc.), and 0.05% TexSpecial Liquid™ Commercial Liquid Denim Lubricant/Softener (EcolabInc.), and a six minute extraction to remove excess liquid.

Each laundered wrapper was inspected for a pass, meaning that noadhesive residue remained on the wrapper, and the tape backing wasintact (i.e., the backing did not disperse, such that the ink was stillcontained on the backing), or in the case of a tissue backing,dispersed; or for a fail, meaning that there was an adhesive residue onthe wrapper and/or the paper backing was not intact, and/or the tissuebacking had not dispersed.

Drop Test

Wrapped bundles were prepared as described in the Post-sterilizationWrapper Closure Test. The taped bundles were dropped as described inASTM D4169-90 using Hazard Element A for a Filled Bag, and ASTM D959-80with the following variation: the bundles were dropped from heights of38 cm and 91.5 cm on each of the two ends and on the side of the bundleaway from the tape and on the tape. The results were described as: Pmeaning passed, bundle still closed; P-T meaning passed, bundle stillclosed, but with a slight tear in the backing; F-T meaning failed,bundle opened because the backing tore; F-O meaning failed, bundleopened because the tape popped off the bundle without tearing.

The invention will be further illustrated by reference to the followingnon-limiting Examples. All parts and percentages are expressed as partsby weight unless otherwise indicated.

EXAMPLES 1-14

An acrylate:vinyl carboxylic acid copolymer was prepared, generally asdescribed in U.S. Pat. No. RE 24,906. The monomers, 75 weight percentbutyl acrylate/25 weight percent acrylic acid were dissolved in ethylacetate in a 75 gallon reactor. 0.3 weight percentazobisisobutyronitrile (VAZO™ 64; E.I. dupont Nemours, Wilmington, Del.)as a polymerization initiator and 2.3 weight percent isopropanol as achain transfer agent were added to the reactor. A nitrogen purge wasintroduced for two minutes at a flow rate of 1 liter/minute. Thesolution was held at 55° C. for about 24 hours, at which timecopolymerization was 99% completed. Sufficient ethyl acetate was addedto the solution to produce a system having a solids content of about30%.

The plasticizer, the tackifier, and the alkali metal hydroxideneutralizing agent(s), if any, in a 4N 50:50 methanol and water (v/v)solution were sequentially blended into the solvent system containingthe copolymer solids. Sufficient methanol and water was added to bringthe system to a weight ratio of 80:15:5 ethyl acetate:methanol:water.The mixture was agitated to produce a colorless to amber, low viscositysolution.

The backing used for the indicator tapes was a 29 pound basis weightKraft paper ("M-2383 Smooth Crepe Semi-Bleached Kraft Saturating Paper";Mosinee Paper Corporation, Mosinee, Wis.).

The Kraft paper was gravure printed in lines with a sulfur-lead inksystem in a binder system. The ink system contained 38% binder, 23%sulfur, 15% lacquer thinner, 23% lead carbonate and 1% clay("Bertone-38"; NL Chemicals, Hightstown, N.J.). The binder systemcontained 24% nitrocellulose ethyl alcohol; 3% phenol-formaldehyde resin("Beckcite 24-102"; BTL Specialty Resins, Toledo, Ohio); 9% tricresylphosphate; 14% butyl alcohol; 27% xylene and 23% butyl acetate.

The ink printed Kraft paper was strengthened using a vulcanized naturalrubber-wood rosin system coated onto the paper. The rubber system was23% natural rubber (Goodyear Tire and Rubber Co., Akron, Ohio); 6% zincoxide (Sherwin Williams, Cleveland, Ohio); 3% titanium dioxide ("TypeA-140"; New Jersey Zinc Co., Palmerton, Pa.); 29% wood rosin ("Tenex36-710"; Reichold Chemicals Inc., Oakbrook, Ill.); 2% calcium litholpigment (Hercules Inc.); and 37% mineral spirits. The vulcanizer used tocrosslink the rubber system was 40% white mineral oil (Type #31 USP;AMOCO Chemical Corp., Chicago, Ill.); 15% tetramethylthirum disulfideaccelerator (RT Vanderbilt Co., Norwalk, Conn.); and 45%ortho-pentamethylenethiuram sulfads (RT Vanderbilt Co.).

The printed, saturated paper backing was then treated to decreasemoisture penetration with a solution contained 19% butyl alcohol, 0.2%phosphoric acid, 9% urea, 0.8% aqueous ammonia, 31% formaldehyde, 6%isopropyl alcohol, 10% acrylic polymer ("Elvacite 2044"; E.I. dupontNemours, Wilmington, Del.); 9% butanol and 15% xylene.

The pressure sensitive adhesives in the solvent system were coated onthe Kraft paper at 0.68 grams per 154.8 cm² (24 in²) using a standardlaboratory knife coater, with drying for 15 minutes in a forced air ovenat 100° C.

Table 1 shows the formulations of water-dispersible, pressure sensitiveadhesives coated on Example Indicator Tapes Nos. 1-14. Tables 2 and 3show the initial adhesion, post-sterilization adhesion,pre-sterilization wrapper closure (T(0)), post-sterilization wrapperclosure (T(A)), and dispersibility of the indicator tapes of Examples1-14 on untreated 100% cotton wrappers and fluorochemically-treatedpolyester wrappers respectively.

When interpreting the results contained in Tables 1-12 and FIGS. 2-12,the data should be analyzed for trends as opposed to specific numericalvalues. This is due to the inherent variability in the test wrappers.This variability arises, at least in part, from the wearing effects ofage, harshness of wash conditions, and residual chemicals present fromlaundering.

                                      TABLE 1                                     __________________________________________________________________________    Formulation of water-dispersible, pressure sensitive adhesives coated on      Example Indicator Tapes Nos. 1-14.                                                  Copolymer                                                                            Plasticizer                                                                          Plasticizer                                                                          Tackifier                                                BA/AA  PE-510 RE-410 Foral AX                                                                             Neutralization                                                                         Solids                             Ex. No.                                                                             (parts)                                                                              (parts)                                                                              (parts)                                                                              (parts)                                                                              (%)      (%)                                __________________________________________________________________________    1     100    89            23     00.0     35.0                               2     100    89            23     12.5     35.0                               3     100    89            23     25.0     35.0                               4     100    89            23     37.5     35.0                               5     100    89            23     50.0     35.0                               6     100    89            23     75.0     35.0                               7     100    89            23     100.0    35.0                               8     100           89     23     00.0     35.0                               9     100           89     23     12.5     35.0                               10    100           89     23     25.0     35.0                               11    100           89     23     37.5     35.0                               12    100           89     23     50.0     35.0                               13    100           89     23     75.0     35.0                               14    100           89     23     100.0    35.0                               __________________________________________________________________________

                                      TABLE 2                                     __________________________________________________________________________    Initial adhesion, post-sterilization adhesion, pre-sterilization wrapper      closure (T(o)),                                                               post-sterilization wrapper closure (T(a)), and dispersibility of              pressure-sensitive                                                            adhesive coating for Example Indicator Tapes Nos. 1-14 on T-180 untreated     wrappers.                                                                                     Post-Sterilized                                                                         Wrapper Wrapper Closure                                   Initial Adhesion                                                                        Adhesion  Closure T(o)                                                                          T(A)      Dispersibility                    Ex. No.                                                                             (Newton/2.54 cm)                                                                        (Newton/2.54 cm)                                                                        (pass/fail).sup.a                                                                     (pass/fail)                                                                             (pass/fail)                       __________________________________________________________________________    1     5.1       2.5       P-E     P         P                                 2     5.8       2.8       P       P         P                                 3     3.9       3.4       P-E     P         P                                 4     2.1       3.2       P-E     P         P                                 5     2.6       2.9       P-E     P         P                                 6     1.6       3.0       P-E     P         P                                 7     2.7       2.9       P-E     P         P                                 8     1.6       3.3       F-P     P         P                                 9     2.4       1.4       P-E     P         P                                 10    2.1       2.1       F-P     P         P                                 11    1.6       4.6       F-P     P         P                                 12    1.6       4.8       F-P     P         P                                 13    0.7       4.4       F-P     P         P                                 14    1.1       5.0       F-P     P         P                                 __________________________________________________________________________     .sup.a P = pass, PE = pass with edge lift, FP = failed popped off        

                                      TABLE 3                                     __________________________________________________________________________    Initial adhesion, post-sterilization adhesion, pre-sterilization wrapper      closure (T(o)),                                                               post-sterilization wrapper closure (T(A)), and dispersibility of pressure     sensitive adhesive                                                            coating for Example Indicator Tapes Nos. 1-14 as WrapPel ™ 2               fluorochemically-treated wrappers.                                                                       Wrapper Wrapper Closure                                  Initial Adhesion                                                                        Sterilized Adhesion                                                                      Closure T(o)                                                                          T(o)      Dispersibility                   Ex. No.                                                                             (Newton/2.54 cm)                                                                        (Newton/2.54 cm)                                                                         (pass/fail).sup.a                                                                     (pass/fail)                                                                             (pass/fail)                      __________________________________________________________________________    1     1.6       3.1        F-C     P-E       P                                2     0.9       2.5        F-C     F-P       P                                3     1.9       4.2        P-E     P-E       P                                4     1.2       2.6        F-C     P-E       P                                5     0.5       2.4        F-P     P-E       P                                6     0.4       2.1        F-P     P-E       P                                7     0.6       3.0        F-P     P-E       P                                8     0.0       2.5        F-P     F-P       P                                9     1.5       3.2        F-C     P-E       P                                10    1.2       3.3        F-P     P-E       P                                11    1.1       3.5        F-P     P-E       P                                12    0.6       4.3        F-P     P-E       P                                13    0.3       3.8        F-P     P-E       P                                14    0.4       4.5        F-P     P-E       P                                __________________________________________________________________________     .sup.a PE = pass with edge lift, FC = failed curled up, FP = failed poppe     off                                                                      

Tables 2 and 3, and FIGS. 2 and 3 show that the maximum initial adhesionof the Example Indicator Tapes occurs between 0% and 25% neutralizationfor both the adhesive formed with the PE-510 and the RE-410 plasticizerson both untreated 100% cotton wrappers and WrapPel™ 2fluorochemically-treated polyester wrappers. In addition, Table 2 showsthat the adhesives formed with the PE-510 plasticizer exhibit sufficientadhesion to maintain untreated wrappers in a closed position prior tosterilization. Conversely, adhesives formed with the RE-410 plasticizer,in most instances, did not exhibit sufficient adhesion to maintainuntreated wrappers in a closed position prior to sterilization.

With respect to untreated wrappers, if sufficient initial adhesion canbe maintained, post-sterilization wrapper closure and dispersibility ofthe adhesive will perform as required. This appears, at least in part,to be due the flow of the adhesives into the fabric of the wrappers whensubjected to higher temperature sterilization conditions. Thus, asdemonstrated in Tables 2 and 3, and FIGS. 4 and 5, post-sterilizationadhesion is not as critical a factor in the successful use of theExample indicator tapes.

With respect to WrapPel™ 2 fluorochemically-treated polyester wrappers,initial adhesion is also a critical requirement. In this regard, Table 3shows the choice of useful indicator tapes is more limited than with theuntreated wrappers. Specifically, only Example indicator tape No. 3displayed sufficient initial adhesion to maintain the WrapPel™ 2 treatedwrapper in a closed position prior to sterilization. It appears that theselection of plasticizer and degree of neutralization of thewater-dispersible adhesive is more limited when designing indicatortapes for treated sterilization wrappers, such as the WrapPel™ 2wrapper.

All formulations dispersed when laundered under institutionalconditions, independent of the degree of neutralization of thewater-dispersible adhesive employed.

EXAMPLES 15-28

Indicator tapes 15-28 utilize the same backing and the same adhesives asExample Indicator Tapes 1-14 except the plasticizer was reduced to 84parts from 89 parts and the tackifier was increased to 25 parts from 23parts. Table 4 shows the formulations of water-dispersible, pressuresensitive adhesives coated on Example Indicator Tapes Nos. 15-28. Table5 shows the initial adhesion, post-sterilization adhesion,pre-sterilization wrapper closure (T(0)), post-sterilization wrapperclosure (T(A)), dispersibility and drop test results from 38 cm and 91.5cm for the indicator tapes of Examples 15-28 on untreated 100% cottonwrappers. Table 6 shows the initial adhesion and post-sterilizationadhesion of the indicator tapes of Examples 15-28 onfluorochemically-treated polyester wrappers.

                                      TABLE 4                                     __________________________________________________________________________    Formulation of water-dispersible, pressure sensitive adhesives coated on      Example Indicator Tapes Nos. 15-28.                                                 Copolymer                                                                            Plasticizer                                                                          Plasticizer                                                                          Tackifier                                                BA/AA  PE-510 RE-410 Foral AX                                                                             Neutralization                                                                         Solids                             Ex. No.                                                                             (parts)                                                                              (parts)                                                                              (parts)                                                                              (parts)                                                                              (%)      (%)                                __________________________________________________________________________    15    100    84            25     00.0     35.0                               16    100    84            25     12.5     35.0                               17    100    84            25     25.0     35.0                               18    100    84            25     37.5     35.0                               19    100    84            25     50.0     35.0                               20    100    84            25     75.0     35.0                               21    100    84            25     100.0    35.0                               22    100           84     25     00.0     35.0                               23    100           84     25     12.5     35.0                               24    100           84     25     25.0     35.0                               25    100           84     25     37.5     35.0                               26    100           84     25     50.0     35.0                               27    100           84     25     75.0     35.0                               28    100           84     25     100.0    35.0                               __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    Initial adhesion, post-sterilization, pre-sterilization wrapper closure       (T(o)),                                                                       post-sterilization wrapper closure (T(A)), dispersibility of pressure         sensitive                                                                     adhesive coating, and maintenance of closed wrapped bundles dropped from      38 cm and                                                                     91.5 cm for Example Indicator Tapes Nos. 15-28 using T-180 untreated          wrappers.                                                                                   Post-Sterilize                                                                         Wrapper Closure                                                                         Wrapper Closure                                                                        Drop Test                                                                            Drop test                         Initial Adhesion                                                                       Adhesion T(o)      T(o)     @38 cm @91.5 cm                                                                            Dispersibility         Ex. No.                                                                            (Newton/2.54 cm)                                                                       (Newton/2.54 cm)                                                                       (pass/fail).sup.a                                                                       (pass/fail)                                                                            (pass/fail)                                                                          (pass/fail).sup.b                                                                   (pass/fail)            __________________________________________________________________________    15   3.2      3.2      P-E       P        P      P     P                      16   3.2      2.5      P-E       P        P      P     P                      17   2.4      3.5      P-E       P        P      P     P                      18   1.0      2.8      F-C       P        P      P     P                      19   1.0      4.6      F-C       P        P      P     P                      20   1.0      2.2      F-C       P        P      P     P                      21   0.1      2.0      F-P       P        P      P     P                      22   0.1      3.3      F-P       P        P      F-O   P                      23   1.6      3.4      F-P       P        P      P     P                      24   1.3      3.5      F-P       P        P      P     P                      25   0.3      2.7      F-P       P        P      P     P                      26   0.6      2.7      F-P       P        P      P     P                      27   >0.1     2.6      F-P       P        P      P     P                      28   >0.1     2.5      F-P       P        P      P     P                                                                             P                      __________________________________________________________________________     .sup.a PE = pass with edge lift, FC = failed curled up, FP = failed poppe     off                                                                           .sup.b P = pass, FO = failed by opening                                  

                  TABLE 6                                                         ______________________________________                                        Initial adhesion and post-sterilization adhesion                              for Example Indicator Tapes Nos. 15-28 on WrapPel ™                        2 fluorochemically-treated wrappers.                                                                  Post-Sterilized                                                  Initial Adhesion                                                                           Adhesion                                              Ex. No.    (Newton/2.54 cm)                                                                           (Newton/2.54 cm)                                      ______________________________________                                        15         0.6          1.9                                                   16         1.3          1.7                                                   17         0.7          1.7                                                   18         0.3          1.4                                                   19         0.1          1.5                                                   20         0.1          1.8                                                   21         >0.1         1.2                                                   22         >0.1         2.2                                                   23         0.5          2.4                                                   24         0.4          2.8                                                   25         0.1          2.8                                                   26         >0.1         2.2                                                   27         >0.1         1.8                                                   28         >0.1         1.8                                                   ______________________________________                                    

Tables 5 and 6, and FIGS. 6 and 7, show analogous results to those seenfor Example indicator tapes Nos. 1-14. In addition, Table 5, shows thatby reducing the amount of plasticizer included in the water-dispersibleadhesives, that the number of useful indicator tapes has also beenreduced. Specifically, only those indicator tapes using the PE-510plasticizer, and with neutralization levels between 0% and 25% displayedsufficient initial adhesion to maintain the untreated wrappers in aclosed position prior to sterilization. Thus, it appears that the degreeof neutralization becomes a more important factor at reduced plasticizerlevels. Furthermore, Table 5 shows that once the indicator tape has beensterilized, that its backing strength and post-sterilization adhesionare sufficient in all but one instance to keep the untreated wrapperclosed, and withstand the normal handling associated with the transferand storage of wrapped package.

Table 6 was not compared with respect to closure et al. because initialadhesion values were too low on the treated wrappers.

COMPARATIVE EXAMPLE 29

A transfer adhesive (#905 Repulpable Flying Splice Tape"; 3M, St. Paul,Minn.) supplied at 0.05 mm (2 mils) thickness was laminated to the Kraftpaper backing described in Example Indicator Tape Nos. 1-14. Initialadhesion to untreated wrappers was 2.6 Newton/2.54 cm andPost-sterilization adhesion was 2.9 Newton/2.54 cm. Comparative ExampleIndicator Tape No. 29 passed the Pre-sterilization Wrapper Closure TestT(0) with edge lift. Comparative Example 29 also passed thePost-sterilization Wrapper Closure Test T(A), Dispersibility of thepressure sensitive adhesive coating, and maintenance of closed wrappedbundles dropped from 38 cm and 91.5 cm using T-180 untreated cottonwrappers. For WrapPel™ 2 fluorochemically-treated wrappers the initialadhesion was 0.6 Newton/2.54 cm and 3.9 Newton/2.54 cm forpost-sterilization adhesion. The initial adhesion was so low thatfurther testing was not done. However, this adhesive was improperlyreacted with the ink system used as the sterilization indicator. Inparticular, the adhesive caused the ink system to change color when inroll form. The phenomenon is believed to be due to the fact that theneutralizing agent in the adhesive is catalyzing the ink reaction priorto sterilization.

COMPARATIVE EXAMPLES 30-43

For comparison purposes the pressure sensitive adhesives in the solventsystem from Example Indicator Tape Nos. 15-18 were coated at the samecoating weight on a 8 lb basis weight, water dispersible tissue paper(8# Crystex Tissue Paper"; Crystal Paper Company, Middletown, Ohio).

Table 7 shows the initial adhesion, post-sterilization adhesion,pre-sterilization wrapper closure, post-sterilization wrapper closure,and dispersibility of the indicator tapes of Comparative Examples 30-43on untreated 100% cotton wrappers. Table 8 shows the initial adhesionand post-sterilization adhesion of the indicator tapes of ComparativeExamples 30-43 on fluorochemically-treated polyester wrappers (WrapPel™2).

                                      TABLE 7                                     __________________________________________________________________________    Initial adhesion, post-sterilization, pre-sterilization wrapper closure       (T(o)),                                                                       post-sterilization wrapper closure (T(A)), dispersibility of pressure         sensitive                                                                     adhesive coating, and maintenance of closed wrapped bundles dropped from      38 cm and                                                                     91.5 cm for Example Indicator Tapes Nos. 30-43 using T-180 untreated          wrappers.                                                                                   Post-Sterilize                                                                          Wrapper Closure                                                                        Wrapper Closure                                                                        Drop Test                                                                            Drop test                    Comp Initial Adhesion                                                                       Adhesion  T(o)     T(A)     @38 cm @91.5 cm                                                                            Dispersibility         Ex. No.                                                                            (Newton/2.54 cm)                                                                       (Newton/2.54 cm).sup.a                                                                  (pass-/fail).sup.b                                                                     (pass/fail).sup.b                                                                      (pass/fail).sup.b                                                                    (pass/fail).sup.b                                                                   (pass/fail)            __________________________________________________________________________    30   2.5      3.5 B     P        P-T      F-T    F-T   P                      31   2.4      3.2 B     P        F-T      F-T    F-T   P                      32   1.6      4.8 B     P        F-T      F-T    F-T   P                      33   1.4      4.0 B     P        P        F-T    F-T   P                      34   0.8      3.6 B     P        P        P      F-T   P                      35   1.7      6.2 B     P        P        P-T    F-T   P                      36   0.6      4.5 B     P        P-T      F-T    F-T   P                      37   0.1      1.7 B     P-E      F-T      F-T    F-T   P                      38   1.3      4.0 B     P        P        F-T    F-T   P                      39   1.4      5.0 B     P        P        F-T    F-T   P                      40   0.7      10.6 B    P        P        P-T    F-T   P                      41   0.7      4.4 B     P        P        F-T    F-T   P                      42   0.1      3.7 B     P-E      P        F-T    F-T   P                      43   0.1      3.1 B     F-P      P-T      F-T    F-T   P                                                                             P                      __________________________________________________________________________     .sup.a B = tissue paper backing broke during adhesion testing                 .sup.b P = pass, PE = pass with edge lift, PT = pass with some tear in        backing, FP = failed popped off, FT = failed by torn backing             

                  TABLE 8                                                         ______________________________________                                        Initial adhesion and post-sterilization adhesion for                          Comparative Example Indicator Tapes Nos. 30-43 on                             WrapPel 2 ™ fluorochemically-treated wrappers.                             ______________________________________                                        30             0.5     1.2 B                                                  31             0.5     1.2 B                                                  32             0.7     2.1 B                                                  33             0.4     1.2                                                    34             0.2     0.9                                                    35             0.1     1.6 B                                                  36             >0.1    1.0 B                                                  37             >0.1    0.8 B                                                  38             0.4     1.5 B                                                  39             0.4     1.1                                                    40             0.1     1.5                                                    41             0.2     1.3                                                    42             >0.1    1.4                                                    43             >0.1    1.1                                                    ______________________________________                                         .sup.a B = tissue paper backing broke during adhesion testing            

Tables 7 and 8 show analogous results to those results seen for initialadhesion for Example indicator tapes 15-28. The pre-sterilizationwrapper closure results were improved when compared to Example indicatortapes 15-28, as the conformability of the tissue paper backing helped toprevent the edge lift and popping from occurring. Post-sterilizationwrapper closure tests were worse when compared to Example indicatortapes 15-28, as Examples 30-43 showed a greater degree of failure due tothe low strength tissue backing becoming torn during the pressurizationof the sterilization cycle. This lack of backing strength is furtherillustrated in the drop test data. Only one sample survived the 38 cmdrop test, and all samples failed at the 91.5 cm drop level. Table 8 wasnot compared with respect to wrapper closure, dispersibility and droptests, because initial adhesion values were too low on the treatedwrappers.

COMPARATIVE EXAMPLES 44-45

The pressure sensitive adhesive in solvent system from Example 17 (Table4) was coated on an unoriented polyvinyl alcohol backing, 0.06 mm (2.5mils) thick (VINEX™ Polyvinyl Alcohol Film; Air Products and Chemicals,Inc., Allentown, Pa.) at a coating weight of 0.68 g/154.8 cm² forComparative Example 44. A transfer adhesive (No. 905, Repulpable FlyingSplice Tape; 3M Company, St. Paul, Minn.) was laminated on the samevinyl backing as Comparative Example 44 to yield Comparative Example 45.Table 9 shows the initial adhesion, post-sterilization adhesion,pre-sterilization wrapper closure, post-sterilization wrapper closure,dispersibility, drop test results at 38 cm and 91.5 cm for the indicatortapes of Comparative Examples 44-45. The results show that the vinyldispersible backing melted under sterilization conditions.

                                      TABLE 9                                     __________________________________________________________________________    Initial adhesion, post-sterilization adhesion, pre-sterilization wrapper      closure (T(o)),                                                               post-sterilization wrapper closure (T(A)), dispersibility of pressure         sensitive adhesive                                                            coating, and maintenance of closed wrapped bundles dropped from 38 cm and     9.15 cm                                                                       for Comparative Example Indicator Tapes Nos. 44-45 using T-180 untreated      wrappers.                                                                                   Post-Sterilize                                                                         Wrapper Closure                                                                         Wrapper Closure  Drop Test                                                                           Drop Test             Comp Initial Adhesion                                                                       Adhesion T(O)      T(A)     Dispersibility                                                                        @38 cm                                                                              @91.5 cm              Ex. No.                                                                            (Newton/2.54 cm)                                                                       (Newton/2.54 cm)                                                                       (pass/fail)                                                                             (pass/fail)                                                                            (pass/fail)                                                                           (pass/fail)                                                                         (pass/fail)           __________________________________________________________________________    44   1.2      Melt     P-E       Melt     Pass    Melt  Melt                  45   1.8      Melt     P-E       Melt     Pass    Melt  Melt                  __________________________________________________________________________

EXAMPLES 46-55

The pressure sensitive adhesives in the solvent system were coated onKraft paper at 0.68 g/154.8 cm². The amount of PE-510 plasticizer wasvaried to determine its effect on performance properties. Table 10 showsthe formulations of water-dispersible, pressure sensitive adhesivescoated on Example indicator tapes Nos. 46-55. Tables 11 and 12 show theinitial adhesion, post-sterilization adhesion, pre-sterilization wrapperclosure, post-sterilization wrapper closure and dispersibility of theindicator tapes of Examples 46-55 on untreated 100% cotton wrappers andon fluorochemically-treated polyester wrappers respectively.

                  TABLE 10                                                        ______________________________________                                        Formulation of water dispersible,                                             pressure sensitive adhesives coated on Example                                Indicator Tapes Nos. 46-55.                                                        Copolymer Plasticizer                                                                             Tackifier                                                                             Neutral-                                     Ex.  BA/AA     PE-510    Foral AX                                                                              ization                                                                              Solids                                No.  (parts)   (parts)   (parts) (%)    (%)                                   ______________________________________                                        46   100       120       25      0      35.0                                  47   100       120       25      12.5   35.0                                  48   100       120       25      25     35.0                                  49   100       120       25      37.5   35.0                                  50   100       120       25      50     35.0                                  51   100       120       25      75     35.0                                  52   100       120       25      100    35.0                                  53   100       105       25      25     35.0                                  54   100       135       25      25     35.0                                  55   100       150       25      25     35.0                                  ______________________________________                                    

                                      TABLE 11                                    __________________________________________________________________________    Initial adhesion, post-sterilization adhesion, pre-sterilization wrapper      closure (T(o)),                                                               post-sterilization wrapper closure (T(A)), and dispersibility of              pressure-sensitive                                                            adhesive coating for Example Indicator Tapes Nos. 46-55 on untreated          wrappers.                                                                                     Post-Sterilized                                                                         Wrapper Wrapper Closure                                   Initial Adhesion                                                                        Adhesion  Closure T(o)                                                                          T(A)      Dispersibility                    Ex. No.                                                                             (Newton/2.54 cm)                                                                        (Newton/2.54 cm)                                                                        (pass/fail).sup.a                                                                     (pass/fail)                                                                             (pass/fail)                       __________________________________________________________________________    46    .8        2.1       P       P         P                                 47    2.9       1.3       P       P         P                                 48    2.4       1.5       P       P         P                                 49    1.6       2.0       P       P         P                                 50    .9        2.1       P       P         P                                 51    .4        1.9       P       P         P                                 52    .2        2.1       P-E     P         P                                 53    1.4       2.1       P       P         P                                 54    2.5       1.4       P       P         P                                 55    3.2       1.1       P       P         P                                 __________________________________________________________________________     .sup.a P = pass, PE = pass with edge lift                                

                                      TABLE 12                                    __________________________________________________________________________    Initial adhesion, post-sterilization adhesion, pre-sterilization wrapper      closure (T(o)),                                                               post-sterilization wrapper closure (T(A)), and dispersibility of pressure     sensitive adhesive                                                            coating for Example Indicator Tapes Nos. 46-55 as WrapPel ™ 2              fluorochemically-treated wrappers.                                                                       Wrapper Wrapper                                          Initial Adhesion                                                                        Sterilized Adhesion                                                                      Closure T(o)                                                                          Closure T(o)                                                                          Dispersibility                     Ex. No.                                                                             (Newton/2.54 cm)                                                                        (Newton/2.54 cm)                                                                         (pass/fail).sup.a                                                                     (pass/fail).sup.a                                                                     (pass/fail)                        __________________________________________________________________________    46    .4        2.1        F-C     P-E     P                                  47    .4        1.9        P-E     P-E     P                                  48    .1        2.0        F-C     P-E     P                                  49    .1        1.7        F-C     F-P     P                                  50    >.1       1.8        F-P     P-E     P                                  51    >.1       2.0        F-P     P-E     P                                  52    >.1       2.0        F-P     F-P     P                                  53    .3        2.7        P-E     P-E     P                                  54    .4        2.0        P-E     P-E     P                                  55    .6        1.9        F-C     P-E     P                                  __________________________________________________________________________     .sup.a PE = pass with edge lift, FC = failed curled up, FP = failed poppe     off                                                                      

Tables 11 and 12 and FIG. 8 show Example indicator tapes 46-52 haveanalogous results to indicator tapes 1-7. However, Examples 46-52 showimproved pre-sterilization wrapper closure results on untreatedwrappers. On treated wrappers Examples 46-52 also show analogous resultsto Examples 1-7, with only one example indicator tape (No. 47)performing adequately. Overall, it can be seen that edge lift isdecreased, while overall performance is not diminished when increasingthe plasticizer level in the adhesive composition up to 120 parts. Theseimproved results take place even though coating weight has decreasedfrom 0.68 g/154.8 cm² to 0.58 g/154.8 cm².

For examples 48 and 53-55, Table 11 and FIG. 9 show that on untreatedwrappers initial adhesion increases with increasing plasticizer level,while post sterilized adhesion decreased with increasing plasticizerlevel. However, all Examples formed acceptable indicator tapes.

Table 12 and FIG. 10 show that on treated wrappers, initial adhesionincreases with increasing plasticizer level, while post sterilizedadhesion decreased with increasing plasticizer level. However, onlyExamples 53 and 54 kept the bundle closed prior to sterilization.

COMPARATIVE EXAMPLE 56

A commonly used indicator tape for wrapper closure (No. 1222 autoclavetape; 3M Company), was used for comparison of performance properties onuntreated wrappers and treated wrappers. On untreated wrappers, initialadhesion was 1.2N/2.54 cm, post-sterilization adhesion was 1.9N/2.54 cm,and the indicator tape passed pre and post-sterilization wrapper closuretests. On treated wrappers, initial adhesion was 0.3N/2.54 cm,post-sterilization adhesion was 0.6N/2.54 cm, and the indicator tapefailed both pre- and post-sterilization wrapper closure tests. Theadhesive for the indicator tape failed to disperse during laundering forboth treated and untreated wrappers.

EXAMPLES 57-58

The pressure sensitive adhesive described for Example indicator tape No.48 was coated on Kraft paper at 0.87 g/154.8 cm2 for Example 57, and at1.04 g/154.8 cm2 for Example 58. These Examples were done to show theeffect of increased coating weight on performance properties. Exampleindicator tape No. 57 on untreated wrappers had initial adhesion of2.9N/2.54 cm and post-sterilization adhesion of 1.8N/2.54 cm. Exampleindicator tape No. 58 on untreated wrappers had initial adhesion of3.2N/2.54 cm and post-sterilization adhesion of 2.2N/2.54 cm.

Example indicator tape No. 57 on treated wrappers had initial adhesionof 0.7N/2.54 cm and post-sterilization adhesion of 2.2N/2.54 cm. Exampleindicator tape No. 58 on treated wrappers had initial adhesion of1.1N/2.54 cm and post-sterilization adhesion of 4.2N/2.54 cm.

The Example indicator tape Nos. 57 and 58 passed the pre- andpost-sterilization wrapper closure test on untreated wrappers. Ontreated wrappers, both Examples 57 and 58 passed pre- andpost-sterilization wrapper closure with edge lift. Both Exampleindicator tapes passed dispersibility of the pressure sensitive adhesiveon untreated and treated wrappers.

FIG. 11 shows for Examples 48, 57 and 58, that increasing coating weightincreased initial adhesion, post-sterilized adhesion, and improved pre-and post-sterilization wrapper closure results on untreated wrappers.FIG. 12 shows for Examples 48, 57 and 58, that increasing coating weightincreased initial adhesion, post-sterilized adhesion, and improved pre-and post-sterilization wrapper closure results on treated wrappers. Thehigher coating weight at this formulation allows for two acceptableindicator tapes Nos. 57 and 58 for treated wrappers to be formed.

Example 59 and Comparative Example 60

Example indicator tape No. 59 was made as described for Exampleindicator tape No. 48. Comparative Example indicator tape No. 60 was acommonly used indicator tape for ethylene oxide sterilization (No. 1224,ethylene oxide indicator tape; 3M Company). These example tapes weretested as in Examples 1-14, except that they were sterilized in a No.4XL Ethylene Oxide Sterilizer (3M Company) using the cold cycle and a 3Mbrand Steri-Gas™ No. 4-100 ethylene oxide cartridge.

On untreated wrappers, Example indicator tape No. 59 had initialadhesion of 2.4N/2.54 cm and post-sterilization adhesion of 6.0N/2.54cm. Comparative Example indicator tape No. 60 on untreated wrappers hadinitial adhesion of 0.9N/2.54 cm and post-sterilization adhesion of3.5N/2.54 cm. Example indicator tape No. 59 and Comparative Exampleindicator tape No. 60 on untreated wrappers passed pre- andpost-sterilization wrapper closure test.

On treated wrappers, Example indicator tape No. 59 had initial adhesionof 0.1N/2.54 cm and post-sterilization adhesion of 5.6N/2.54 cm.Comparative Example indicator tape No. 60 on treated wrappers hadinitial adhesion of 0.1N/2.54 cm and post-sterilization adhesion of3.5N/2.54 cm. Example indictor tape No. 59 and Comparative Exampleindicator tape No. 60 on treated wrappers passed pre- andpost-sterilization wrapper closure test with edge lift.

Example indicator tape No. 59 passed the dispersibilty test, whileComparative Example indicator tape No. 60 failed.

Throughout the present application, the following abbreviations havebeen employed.

    ______________________________________                                        Acrylate Monomer                                                              BA    butyl acrylate                                                          Vinyl Carboxylic Acid Monomer                                                 AA    acrylic acid                                                            Tackifier                                                                     AX    colophony acid rosin tackifier, available for Hercules                        Corp. under the trademark "Foral AX"                                    Plasticizer                                                                   PE-510                                                                              poly(oxy-1,2-ethandiyl), alpha-(nonylphenyl)-                                 omega-hydroxy-phosphate, available from Rhone Poulenc                         under the trademark "Rhodafac PE-510"                                   RE-410                                                                              poly(oxy-1,2-ethandiyl), alpha-(nonylphenyl)-                                 omega-hydroxy-phosphate, available from Rhone Poulenc                         under the trademark "Rhodafac RE-410"                                   Neutralization (%)                                                            Percent copolymer acid neutralized with potassium                             hydroxide (KOH).                                                              Solvent                                                                       An Ethyl Acetate/Methanol/Water in a weight ratio                             of 80/15/5.                                                                   Testing Wrappers                                                              WrapPel ™ 2 100% treated polyester commercially                            available from Standard Textile Co., Cincinnati, OH                           T-180 100% cotton T-180 Surgical wrapper commercially                         available from American Linen Supply Co.,                                     St. Paul, MN                                                                  ______________________________________                                    

While in accordance with the patent statutes, description of thepreferred weight fractions, and processing conditions have beenprovided, the scope of the invention is not to be limited thereto orthereby. Various modifications and alterations of the present inventionwill be apparent to those skilled in the art without departing from thescope and spirit of the present invention.

Consequently, for an understanding of the scope of the presentinvention, reference is made to the following claims.

What is claimed is:
 1. An indicator tape comprising:(a) anon-water-dispersible backing having opposing sides and includingthereon a sterilization indicator, and; (b) a moisture-resistant,pressure sensitive adhesive comprising an acrylate-based copolymer incombination with a plasticizer coated on at least one of the opposingsides of the backing, said pressure sensitive adhesive being dispersibleupon immersion in aqueous alkali solutions and said acrylate-basedcopolymer comprising a blend of (a) 100 parts by weight of a copolymerof monomers of (1) about 50-85 weight percent of at least one monomericacrylic acid ester of a nontertiary alkyl alcohol having 2-8 carbonatoms, and (2) about 50-15 weight percent of a vinyl carboxylic acid,(b) about 10 to about 250 parts by weight of a water-dispersible orwater-soluble plasticizer, (c) optionally from about 0 to about 100parts by weight of an acrylate-compatible tackifier; and (d) sufficientalkali metal hydroxide, if any, to neutralize from 0 to 100 percent ofacid moieties in the copolymer; wherein the coated pressure sensitiveadhesive exhibits sufficient adhesion to maintain a wrapped bundle ofarticles in a closed position during sterilization and normal pre- andpost-sterilization handling.
 2. An indicator tape according to claim 1,wherein the non-water-dispersible backing comprises a woven backing, anonwoven backing, a cloth backing, a film backing, a paper backing, afoil backing, or combinations thereof.
 3. An indicator tape according toclaim 1, wherein the sterilization indicator comprises an indicator inkin combination with a binder, said indicator ink being capable ofundergoing a color change when exposed to sterilization conditions. 4.An indicator tape according to claim 3, wherein the indicator inkcomprises a steam sterilization indicator ink, an ethylene oxidesterilization indicator ink, or a combination of a steam sterilizationindicator ink and an ethylene oxide sterilization indicator ink.
 5. Anindicator tape according to claim 4, wherein the steam sterilizationindicator ink comprises a lead carbonate-sulfur indicator ink.
 6. Anindicator tape according to claim 3, wherein the binder comprises anacrylate binder.
 7. An indicator tape according to claim 3, wherein theindicator ink and binder are applied to the substrate by gravureprinting.
 8. An indicator tape according to claim 1, wherein themonomeric acrylic acid ester of a nontertiary alkyl alcohol comprisesbutyl acrylate and the vinyl carboxylic acid comprises acrylic acid. 9.An indicator tape according to claim 8, wherein the copolymer comprises75 weight percent butyl acrylate and 25 weight percent acrylic acid. 10.An indicator tape according to claim 1, wherein the plasticizer isselected from the group consisting of a free acid of a complex organicphosphate ester, a sodium salt of a complex organic phosphate ester, acolophony ester, or a combination thereof.
 11. An indicator tapeaccording to claim 10, wherein the plasticizer comprises apoly(oxy-1,2-ethandiyl), alpha-(nonylphenyl)-omega-hydroxy-phosphateester.
 12. An indicator tape according to claim 1, wherein the backingexhibits sufficient strength that it will not tear during sterilizationand normal pre- and post-sterilization handling.
 13. An indicator tapeaccording to claim 1, wherein the backing comprises a paper backingsaturated with a strengthening agent.
 14. An indicator tape according toclaim 13, wherein the strengthening agent comprises a rubber-basedstrengthening agent.
 15. An indicator tape according to claim 13,wherein the paper backing further includes a moisture-resistant agentcoated thereon.
 16. A method of using an indicator tape as a wrapperclosure comprising:(a) providing an indicator tape comprising anon-water-dispersible backing having opposing sides and includingthereon a sterilization indicator, with a moisture-resistant, pressuresensitive adhesive coated on at least one of the opposing sides of thebacking, said pressure sensitive adhesive being dispersible uponimmersion in aqueous alkali solutions and said acrylate-based copolymercomprising a blend of (a) 100 parts by weight of a copolymer of monomersof (1) about 50-85 weight percent of at least one monomeric acrylic acidester of a nontertiary alkyl alcohol having 2-8 carbon atoms, and (2)about 50-15 weight percent of a vinyl carboxylic acid, (b) about 10 toabout 250 parts by weight of a water-dispersible or water-solubleplasticizer, (c) optionally from about 0 to about 100 parts by weight ofan acrylate-compatible tackifier; and (d) sufficient alkali metalhydroxide, if any, to neutralize from 0 to 100 percent of acid moietiesin the copolymer; and, (b) applying the indicator tape to asterilization wrapper containing a bundle of articles such that thebundle will remain substantially closed during sterilization, and normalpre- and post-sterilization handling.
 17. A method of using an indicatortape according to claim 16, further comprising, laundering thesterilization wrapper after use in an aqueous alkali solution, whereinthe pressure sensitive adhesive will disperse in the aqueous alkalisolution leaving the non-water-dispersible backing containing theindicator ink thereon intact.